The shaft rods hereafter referred to simply as rods, that form the loom shed in a weaving loom are divided into two groups. One group of rods includes the active rods that form the shed. The other group of rods includes the passive rods which do not participate in the weaving process at the time. For making a group of rods passive, it is known to tilt this group out of the working range of the heald frames. The group of passive rods is mechanically arrested in the passive position by clamping means provided at a respective bellcrank lever. It is also known to hold the passive group of rods in the passive position with a magnetic bar. Further, reference is made to our copending U.S. Ser. No. 08/780,056, filed Dec. 23, 1996 which will issue as U.S. Pat. No. 5,810,055 on Sep. 22, 1998. The disclosure of the copending application is incorporated by reference into the present disclosure.
Where the rods are mechanically arrested in their passive position wear and tear is encountered between the rod and the respective arresting clamp at the bellcrank lever. Such wear and tear is due to machine vibrations occurring during a weaving process. The wear and tear can lead to the loosening of the arresting clamp. Such loosening of the rods in their passive position can lead to substantial mechanical damages in the area of the shaft rods and in the area of the heald frame or shaft. Further, the arresting by a mechanical clamp always requires a manual operation to place the rods into the passive arrested position and such manual operation is labor intensive due to the multitude of rods. Any time when the number of rods in the passive group and/or in the active group needs to be changed, an operator must conventionally perform the manual arresting or release operations. Such work is tedious and ergonomically undesirable.
In the case where the rods are magnetically arrested in their passive position, it is necessary to tilt the passive rods with the bellcrank lever about the respective journal point away from or out of the active position and into contact with a permanent magnet for holding the rods in their passive position. This is a substantial improvement over the mechanical clamping. However, there is still room for improvement, especially with regard to the problem that mechanical vibrations of the loom during its weaving operation can cause the disconnection of a rod from the holding magnet, whereby again damages may be caused, resulting in down time due to necessary repairs, thereby reducing the weaving efficiency of the particular loom.
European Patent Publication EP 0,598,163 A1 discloses an apparatus for holding the shaft rods in a loom, wherein the passive rods are held in a mechanism out of the motion range of the active rods. However, this known structure is neither intended nor suitable for holding the passive rods with their couplings in such a way that a coupling of the rods with the coupling portion secured to the heald frame can be accomplished without the help of an operator. In fact, the operator needs additional equipment for performing any repositioning.
European Patent Publication EP 0,699,788 A1 (Vinciguerra et al.), published on Mar. 6, 1996 discloses a quick coupling system for the heald frames of a loom. A flexible tie element (10, 11) is provided for each bellcrank (6, 7) of each rod. The tie elements are hinged at their lower ends to the respective bellcrank and the top end of the tie element is provided with a head suitable for entering a groove of a guide provided with a stop to limit the motion of the head of a tie element into the respective groove in which the rod is then locked. The heads of the tie elements must be properly aimed into their respective guide slots.
European Patent Publication EP 0,712,950 A1 (Cremonesi), published on May 22, 1996, discloses a quick coupling for the connecting rods (6) to their heald frame. The quick coupling includes first hooks (8) connected to the heald frames (2) and facing downwardly from the heald frames and second hooks (9) reaching upwardly from the respective connecting rod (6). The couplings are operated by bellcranks and a lever mechanism.
Conventionally, the passive rods are so prepositioned that, when a rod change is required, the coupling elements on the side of the rods may require manual help from the operator for coupling the rods to the heald frames.